1 /*****************************************************************************
2 * simple.c : simple channel mixer plug-in (only 7/7.1/5/5.1 -> Stereo for now)
3 *****************************************************************************
4 * Copyright (C) 2002 VideoLAN
7 * Authors: Gildas Bazin <gbazin@videolan.org>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
22 *****************************************************************************/
24 /*****************************************************************************
26 *****************************************************************************/
27 #include <stdlib.h> /* malloc(), free() */
31 #include "audio_output.h"
32 #include "aout_internal.h"
34 /*****************************************************************************
36 *****************************************************************************/
37 static int Create ( vlc_object_t * );
39 static void DoWork ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
42 /*****************************************************************************
44 *****************************************************************************/
46 set_description( _("audio filter for simple channel mixing") );
47 set_capability( "audio filter", 10 );
48 set_callbacks( Create, NULL );
51 /*****************************************************************************
52 * Create: allocate trivial channel mixer
53 *****************************************************************************/
54 static int Create( vlc_object_t *p_this )
56 aout_filter_t * p_filter = (aout_filter_t *)p_this;
58 if ( (p_filter->input.i_physical_channels
59 == p_filter->output.i_physical_channels
60 && p_filter->input.i_original_channels
61 == p_filter->output.i_original_channels)
62 || p_filter->input.i_format != p_filter->output.i_format
63 || p_filter->input.i_rate != p_filter->output.i_rate
64 || p_filter->input.i_format != VLC_FOURCC('f','l','3','2') )
69 /* Only conversion to Stereo right now */
70 if( p_filter->output.i_physical_channels !=
71 (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT) ) return -1;
73 /* Only from 7/7.1/5/5.1 */
74 if( (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
75 (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
76 AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) &&
77 (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
78 (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
79 AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT |
80 AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) )
85 p_filter->pf_do_work = DoWork;
86 p_filter->b_in_place = 0;
91 /*****************************************************************************
92 * DoWork: convert a buffer
93 *****************************************************************************/
94 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
95 aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
97 int i_input_nb = aout_FormatNbChannels( &p_filter->input );
98 int i_output_nb = aout_FormatNbChannels( &p_filter->output );
99 float *p_dest = (float *)p_out_buf->p_buffer;
100 float *p_src = (float *)p_in_buf->p_buffer;
103 p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
104 p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
106 if( p_filter->input.i_physical_channels & AOUT_CHAN_MIDDLELEFT )
107 for( i = p_in_buf->i_nb_samples; i--; )
109 *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 4 + p_src[4] / 4;
111 *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 4 + p_src[5] / 4;
116 if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
119 for( i = p_in_buf->i_nb_samples; i--; )
121 *p_dest = p_src[4] + 0.5 * p_src[0] + 0.33 * p_src[2];
123 *p_dest = p_src[4] + 0.5 * p_src[1] + 0.33 * p_src[3];
128 if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;